Production of refractories



Patented Dec. 28, 1937 PRODUCTION OF REFRACTORIES Howard P. Eells, Jr., Willoughby, Ohio, assignor to Basic Dolomite, Incorporated, Cleveland, Ohio, a corporation of Ohio No Drawing. Application ctober30, 1933,

Serial No. 695,954

6 Claims. (01. 106-9) This invention relates to the production of refracton'es; and it is among the objects of the invention to provide a refractory which in conveniently divided form can be handled, and can be shipped in open cars or be exposed to the Weather, rain, etc., without detriment, and can be applied in furnace position as desired. Other objects and advantages will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises, the features hereinafter fully described, and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principle of the invention may be employed.

In proceeding in accordance with the invention, a refractory base-material is crushed to desired size. The base-material may vary somewhat as to its particular chemical composition; however for illustration, reference Will be made to dolomite or magnesian limestones. The material crushed and sized, as by screening, the particular size depending somewhat upon the ultimate usage, the particles are treated to supply to the particle-surfaces a flux ingredient and a water resistant medium. The flux ingredient may be a source of iron oxide, alumina, chromium oxide and like-acting agents, as for instance iron ore, mill scale, bauxite, chrome ore, etc. Iron oxide in the form of mill scale is particularly ad vantageous. The amount of flux ingredient may be for instance from 1 to 7 per cent, and an advantageous feature of the present invention lies in the possibility of keeping the total flux down to a very low minimum. The comminuted flux ingredient may be mixed with the waterresistant medium, the latter comprising such substances as hydrocarbons, tarry materials, pitches, tar-pitch, asphalt and the like, residues from the distillation of tar or petroleum, such media as are capable of carrying the flux ingredient on the particles, and protecting the same irrespective of exposure in handling, and ultimately allowing the material to be burned in place, without detriment from the presence of the tarry-like agent. Where an organic material is employed in such usage, it is soon burned out and eliminated in the furnace heat, incidentally also contributing a binder-function temporarily, and with increasing temperature the flux ingredient comes into operation and provides the final permanent bond and thus integralizes the refractory in place. The

amount of such binder may be merely sufficient to accomplish the functions desired, without unnecessary surplus. While in some cases I may apply the tar or asphalt or the like in emulsion or thinned by a volatile solvent, thus avoiding 1 recourse to heat in the, process, it is generally preferable to use the hydrocarbon in molten form or employ heat at some stage of the process at least. Instead of directly mixing the flux ingredients with the hydrocarbon, I may in some cases first coat the particles of dolomite or the like with the hydrocarbon, and while it is still tacky apply the flux component which then becomes bound in place by the hydrocarbon.

As an example: Dolomite is crushed and is screened to about inch size. The particles are then treated with a fluent mixture of petroleum asphalt and iron oxide in amounts of 2 per cent iron oxide based upon the weight of the dolomite, and. 2 per cent asphaltic petroleum residuum,. such as 85 viscosity at 122 F. Saybolt Furol, and the coated particles are heated to a smoking temperature or at least such as to drive off excess volatile matters and attain a well surfaced and impregnated condition. By stirring or tumbling during the treatment, the individually coated particles remain separate, and the material can then be readily handled and be laid up into place for furnace linings, etc. With a material of pitchcharacter, slight softening by heat when applying in place is of assistance in smooth, successful application even on surfaces of verticality beyond the angle of repose. When the furnace is fired, the tarry material burns off at once, and the flux ingredient proceeds to form the permanent bond integralizing the refractory.

As a further refinement of the invention, the refractory particles before being treated with the flux ingredient and protective medium may be calcined. Calcined dolomite particles for in stance, have heretofore been under the handicap of being susceptible to detriment on exposure. Such particles however, may now be handled in free exposure without detriment, preparatory to final positioning in the furnace or the like. While the calcined particles may be treated cold, employing tarry material or the like thin enough to distribute on the particles, a preferable result is attained if heat is availed of to some extent at least. Thus, the calcined particles still heated from the kiln are in advantageous condition for treating.

As an example: Dolomite is crushed and sized to inch mesh, and is calcined as for instance by burning in a rotary kiln at a temperature of the kiln are then mixed with aflux ingredient, as iron oxide 5-10 per cent and asphalt 1-5 per cent. If the particles be so treated while yet heated or warm, a better impregnation of the material is favored. By stirring or tumbling, the particles remain separate, and the material may then be handled as necessary, and in convenient form to be ultimately applied in final furnace position, and be burned in place. 7 V

In order to attain a more thorough-going penetration of the tarry material orthelikeon: the

' refractory base particles, it is advantageous to first eliminate adsorbed gases from the particle surfaces, such gases being atmospheric oxygen and nitrogen, and in the case where particles have been calcined residual. carbondioxidealso. Heating of the particles eliminates a portion'of the adsorbed gases. But fora morethoroughgoing action, I may also apply a vacuum. This need not beof a hightorder, and convenient scon-. tinuous-type operation maybe hadzby progressing and agitating the refractory base particles in a heated draw-off zone to which a vacuum is applied, the particles being forwarded into admixture with the tarry material or the like, while undergoing agitation, and thence successively into a cooling zone.

Other modes of applying the principle of the invention may be employed-,change being made as regards the details described, provided the features stated in any of the-following claims, or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:--

1. A method of producing": refractories, which comprises crushing a refractory base-material to desired size, applying to the particle-surfaces a water-resistant medium, and while the latter is tacky applying a comminuted flux ingredient without substantial agglomerationof the particles 7 together.

about 2200-2500 F. The calcined particles from 2. A method of producing refractories, which comprises crushing a refractory base-material to desired size, and supplying to the particle-surfaces of the material a flux ingredient in divided state and a water resistant agent to bind the flux ingredient to the particles, without substantial agglomeration of the particles together, and applying such loose coated particles to a furnace wall.

3. A method of producing refractories, which comprises crushing a refractory base-material to desiredsize and supplying to the particle-surfaces of the material aflux ingredient in divided state andtar pitch to bind the flux ingredient to the particles, without substantial agglomeration of the particles together, and applying such loose coated particles to a furnace wall.

4AA method of producing refractories, which comprisescrushing a refractory base-material to desired size, and supplying to the particle-surfaces of the material a fiux ingredient in divided state and asphalt to bind the flux ingredient to the particles without substantial agglomeration of the particles together, and applying such loose coated particles to a furnace wall.

5. A refractory, comprising refractory basematerial in unagglomerated particle-form having its particle-surfaces of the material covered with a flux ingredient from the group consisting of iron and chromium supplying agents and asphalt binding the flux ingredient to the particles, whereby loose particles are had capable of being shoveled and being applied to a wall surface.

6. A refractory, comprising refractory base material in unagglomerated particle form having its particle surfaces of the material covered with an iron oxide flux'ingredient and asphalt binding the flux ingredient on the particles, whereby loose particles are had capable of being shoveled and being applied to a wall surface.

HOWARD P. EELLS, JR. 

